This invention relates to the art of fluid line connector assemblies and, more particularly, to thin-walled, flexible fluid line connector assemblies for use in low-pressure applications, such as for connecting between a gas supply line and a stationary or movable gas appliance, a commercial fryer, for example.
Thin-walled, flexible fluid line connector assemblies have been provided heretofore and generally include a length of thin-walled, corrugated, flexible tubing having opposing non-corrugated tubing ends, a braided sheath supported on the outside of the flexible tubing and secured thereto adjacent the tubing ends, a flare nut retained on each tubing end and a flare fitting cooperable with each flare nut to form a fluid-tight seal therewith. The tubing ends commonly include a generally cylindrical journal portion and a radially outwardly extending flare portion, with the cylindrical journal portion spaced axially inwardly from the flare portion. The braided sheath may be secured to the flexible tubing by any suitable method. For example, a cylindrical inner collar may be fitted onto the cylindrical journal portion of the tubing end prior to the formation of the flare portion. An end of the braided sheath may then be positioned along a portion of the outer surface of the inner collar. A braid retaining collar can then be positioned radially adjacent the braided sheath opposite the inner collar, and crimped radially inwardly to compressively capture the braid against the inner collar. Alternatively, the end of the braided sheath may be soldered, brazed, welded or otherwise fused to a portion of the flexible tubing.
The flare nuts are retained on the non-corrugated tubing ends by the flare portion which is deformed radially outwardly after assembly with the sheath, inner collar, retaining collar and flare nut to engage the flare nut and thereby prevent removal thereof from the length of tubing. To form a fluid-tight seal between the flare nut and the flexible tubing, a flare fitting is threadably engaged into the flare nut. The flare fitting includes a frustoconical leading surface, which compressively engages the flare portion of the tubing end. As the flare fitting and flare nut are threadably tightened together, the frustoconical leading surface of the flare fitting displaces the flare portion of the flexible tubing against an interior surface of the flare nut. This displacement causes the flare portion of the tubing to be compressively engaged between the flare fitting and flare nut, and causes a metal-to-metal seal to form between the tubing, the flare fitting and the flare nut such that the assembly becomes fluid tight.
A disadvantage of connector assemblies of the foregoing nature is that tightening the flare nut and flare fitting together to form the metal-to-metal seal with the flexible tubing causes the flare fitting, flare nut and flexible tubing to become rotatably fixed relative to one another. As such, the flare fitting and flare nut are not able to rotate relative to the thin-walled, flexible tubing. As a result, the flexible tubing can become torsionally stressed during the installation of the connector assembly, such as installation between a gas supply line and a commercial, gas appliance.
Known fluid line connector assemblies are commonly used to form a fluid-tight connection between a gas supply line and a commercial food preparation appliance, such as a fryer. These commercial appliances are often movable to permit cleaning beneath and behind the appliance. As such, the fluid line connector assembly extending between the gas supply line and the appliance is often disconnected to facilitate this mobility of the appliance. To minimize the introduction of torsional stresses from repeated connection and disconnection of the connector assemblies, a quick connect fitting is often installed on at least one of the ends thereof. In certain installations desiring mobility of the appliance without need for disconnection of the connector assembly, swivel fittings may be installed on one or both ends of the assembly. However, each of these foregoing connector assemblies undesirably includes an additional threaded connection or joint which can be the source of leaks.
As mentioned above, the flare fitting and flare nut are threadably connected together to form a metal-to-metal seal with the flexible tubing. Opposite the threaded portion of the flare fitting that engages the flare nut is a male or female pipe thread that would otherwise threadably engage the corresponding thread on the gas supply line or appliance, for example. As such, at least two threaded connections are used at each end of the gas line connector assembly. If additional connecting devices, such as quick-connect fittings or multi-plane swivel fittings, are installed, three or more threaded connections may be used. The more threaded connections that are used, the greater the opportunity for the development of leaks.
Also, connections between end fittings are generally not seamless. Rather, there are normally edges on the fittings, and an axial gap between the fittings that opens radially outwardly from the fluid passages that extend through the fittings. The gap creates an annular cavity that disrupts the flow of fluid between the passages in the fittings. Furthermore, the gaps and edges cause resistance to fluid flow between the passages. Therefore, each additional fitting added to an end of the connector assembly, and the attendant gap and edges from the fitting, causes an increase in the resistance to fluid flow through the completed assembly.
In accordance with the present invention, a thin-walled, flexible fluid line connector assembly is provided that avoids or minimizes the problems and difficulties encountered in connection with connector assemblies of the foregoing nature while promoting an increase in performance and reliability, and maintaining a desired simplicity of structure, economy of manufacture and ease of installation.
More particularly in this respect, a fluid line connector assembly is provided for use in connecting between two fluid lines or a fluid line and an appliance or other device, such as between a gas supply line and a commercial, gas fryer. The fluid line connector assembly includes a length of flexible tubing having a substantially cylindrical tubing end, a base ring supported on the tubing end with a first groove extending radially inwardly from the exterior of the base ring, an end-fitting body having an interior passage extending therethrough with a second groove radially extending into the body from the interior passage, a retaining ring and a sealing member, such as an o-ring. The end-fitting body is positioned along the end of the tubing adjacent the base ring such that the first and second grooves are axially aligned with one another and each groove can receive at least a portion of the retaining ring. The sealing member is positioned between the interior passage of the end-fitting body and the associated tubing end.
Preferably, the length of flexible tubing in the connector assembly will include two generally cylindrical and non-corrugated tubing ends, each having a base ring, an end-fitting body, a retaining ring and one or more sealing members. A braided sheath extends along the exterior of the flexible tubing between the tubing ends. The sheath is secured to each base ring by a braid retaining collar that is crimped to compress a portion of the sheath between the collar and the base ring. The end fittings may include male threads, female threads, or both, or alternatively may be a component of an end connector, such as a swivel fitting or a quick-connect fitting. In any case, however, the end fitting remains rotatable relative to the flexible tubing even after assembly and installation between a gas supply line and a commercial appliance, for example.